Enhanced thermoelectric performance of n-type PbTe through the introduction of low-dimensional C60 nanodots

Lead telluride (PbTe) has long been considered as an ideal p-type thermoelectric material at an intermediate temperature range. However, the relatively low thermoelectric performance of n-type PbTe largely limits the commercial applications of integral PbTe devices. In current work, we report that a significant enhancement of the ZT value of approximate to 1.3 can be achieved at 823 K in PbTe0.998I0.002-0.5%C-60 by adding low-dimensional C-60 nanodots. This remarkable improvement in thermoelectric performance is attributed to the incorporation of C-60 in n-type PbTe matrix, which creates dense nanodots that can simultaneously manipulate electron and phonon transport. On one hand, the dispersion of C-60 nanodots in n-type PbTe matrix leads to highly depressed lattice thermal conductivity (kappa(lat)) (similar to 52%) due to the refinement of grains and the extra phonon scattering centers. On the other hand, the introduction of C-60 nanodots increases the scattering parameter r(x), and brings about the overall improvement of Seebeck coefficient S, especially at room temperature. This work demonstrates the great potential of low-dimensional dopant in optimizing PbTe thermoelectric materials, which should be equally applicable in improving the performance of other thermoelectric materials. (C) 2020 Published by Elsevier B.V.